DOCSLIB.ORG

Thin Silicone Membranes—Their Permeation Properties and Some

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Thin Silicone Membranes—Their Permeation Properties and Some THIN SILICONE MEMBRANES- THEIR PERMEATION PROPERTIES AND SOME APPLICATIONS W. L. Robb General Electric Company* Waterford,N. Y. INTRODUCTION While the permeation of gases through solid materials is often a nuisance and sometimes a hazard, in recent years several useful applications have been found for this phenomenon. For example, H, is purified by diffusion through Pd-Ag foils, 0, partial pressures are measured in instruments dependent on 0, permeat- ing through a plastic membrane, and artificial lungs based on permeation of 0, and CO, through thin polymeric membranes are being developed. These appli- cations are only the beginning, for recent advances in membrane technology portend uses as far afield as water desalination by reverse osmosis and the separation of azeotropes by membrane perm-vaporation. When one wishes to separate noncondensable gases by a membrane technique, his first consideration should be whether a silicone rubber membrane can be used. This stems from the unusually high permeability of silicone rubber, indi- cated in TABLE 1, a tabulation of 0, permeabilities in various membranes. TABLE1 0, PERMEAB~ITIESIN VARIOUS POLYMERS Pro. x loo [ cc’s (CTP), cm Polymer sec, sq cm, cm Hg AP 1 Dimethyl silicone rubber 60 Fluorosilicone 11 Nitrile silicone 8.5 Natural rubber 2.4 Ethyl cellulose 2.1 Polyethylene, low density 0.8 BPA polycarbonate .16 Butyl rubber .14 Polystyrene .12 Polyethylene, high density .1 Cellulose acetate .08 Methyl cellulose .Ol Polyvinyl chloride .014 Polyvinyl alcohol .01 Nylon 6 .004 Polyvinylidene fluoride .003 Mylar .0019 Kel F (unplasticized) .001 Vinylidene chloride-vinyl chloride .0005 Teflon .0004 This Table shows that not only standard dimethyl silicone rubber but also many silicone derivatives have 0, permeabilities higher than even the most permeable nonsilicone plastics. In addition to high permeabilities, silicone rubber also has *Work performed at the General Electric Research & Development Center, Schnectady, N. Y. 119 120 Annals New York Academy of Sciences useful selectivity; i.e., it allows certain gases to permeate faster than others. In fact, these properties suggested that, were it available in a 1-mil, hole-free film and in a form that could be packaged and supported against a high-pressure gradient, silicone rubber could compete with other methods for enriching or extracting certain gases. In addition, certain processes not heretofore possible would become feasible; for example, the creation of an artificial gill for humans. A method to produce such membrane has been developed, and I-mil hole-free silicone rubber, either free or bonded to a porous support cloth, is now avail- able in limited quantity. In light of this availability, it is worthwhile to examine the permeation properties of silicone rubber in greater depth. In addition, the results of an experimental study of three possible applications of the membrane are herein presented; oxygen enrichment, air regeneration in an isolated chamber, and air regeneration underwater. GASPERMEABILITY IN SILICONE RUBBER Experimental Procedure The first published values for the permeability of ordinary gases in silicone rubber are those of Kammerrneyerl, reported in 1957. Barrer et ~1.~~~reported permeabilities of C, and C, hydrocarbons in silicone rubber, and they measured solubilities and diffusion rates of these vapors as well. Other data on the perme- ability of silicones are given by Roberts and Kammermeyer.* Permeabilities measured in this laboratory show no disagreement with pre- viously published values. In this section, new measurements are reported for a variety of gases over a very wide range of parameters such as film thickness, temperature, pressure, gas composition, etc.; in addition, measurements of d8u- sion rates and solubilities in silicone rubber by the “time-lag” method are reported for several gases. Permeability constants measured for many gases and vapors on a sample of filled dimethyl silicone rubber film are given in TABLE 2. This particular silicone rubber consisted of dimethyl siloxane plus 33 % by weight silica filler. The meas- TABLE2 GASPERMEABILITIES IN DIMETHYL-SILICONE RUBBER (25%) ~~~ Pr x 1oD PI x lP cc gas (RTP) cm cc gas (RTP) cm Gas [sec, sq cm, cm Hg .PI Gas [sec, sq cm. cm Hg AP] Hl 65 135 He 35 2640 NHs 590 410 H,O 3600 900 CO 34 2000 Nz 28 940 NO 60 860 60 430 1000 1110 60 CH,OH 1390 325 COCI, 1500 435 Acetone 586 760 Pyridine 1910 1500 Benzene 1080 9000 Phenol 2100 95 Toluene 913 250 Robb: Thin Silicone Membranes 121 urements were made in a conventional two-bulb apparatus that could be evacu- ated initially to less than 10-3 mm Hg pressure. The silicone membrane was supported on a porous paper and screen, and the thickness of the membrane was determined from the weight of a given area of membrane. Following evacuation of both the high- and low-pressure sides of the perme- ability cell, gas was admitted to the high-pressure side from a container of gas at known pressure and volume. Permeability rates were usually measured with only a few centimeters of mercury pressure of the specific gas on the high-pres- sure side. For the “noncondensable” gases, a McLeod gauge was used to measure the pressure buildup on the low-pressure side of the membrane. For the con- densable hydrocarbons, a mercury manometer and cathetometer were used, the vapor pressure on the high-pressure side always being kept below the saturated vapor pressure. Water permeation rate was measured by the weight loss of a membrane-covered cup of water which was kept in a dry environment. Permeation rates are given at 25OC in terms of cc’s of an ideal gas or vapor measured at one atm and 25OC. For condensable vapors, this is an artificial vol- ume that might cause confusion if not realized. Measurement of Gas Solubility and Diffusionin Coeficient The data in TABLE 2 support the hypothesis that permeation of polymeric membranes does not occur by leakage through small holes in the membrane. It will be noted, for example, that helium is one of the least permeable gases in spite of its having the smallest molecular diameter. Carbon dioxide is seen to permeate about ten times as fast as helium, and the aliphatic hydrocarbons are seen to peak at C,, with lower permeation rates being measured for both shorter and longer hydrocarbon molecules. This order of permeabilities for various gases in silicone rubber is consistent with permeation in other polymers. It was first proposed by Graham in 1866, and in greater detail by Wroblewski in 1879, that the permeability rate is really a function of two more basic properties: the solubility (S) of the gas in the polymer and the rate of diffusion (D) of this dissolved gas in the polymer. More specifically, it was proposed that the permeability constant (Pr) was really the product of the dif- fusion rate and solubility; i.e., Pr = D X S. Daynes5 showed that D and S could be determined from permeability meas- urements by the “time-lag” method, provided Fick’s and Henry’s laws apply. By use of this method of measurement, diffusion coefficients and solubilities were TABLB3 SOLUBILITIESAND DIFFUSIONRATES OF GASESIN SILJCONERUBBER He 28.0 35.5 60 0.045 HI 21.5 66 43 .12 CH, 21.5 94 12.7 57 N. 28 28.1 15 .15 0; 21.4 62 16 .31 Ar 27.5 61.3 14 .33 CO, 27.6 323 11 2.2 C,H,O 26 UlOOO c5 15 NOTE: Pr = 75 cm Hg/atm 122 Annals New York Academy of Sciences SILICONE RUBBER IW > A ..I NATURAL RUBBER (8) " r7 U AA A LOW DENSITY PE(7) r A H2 Ne O2 Kr NH3 CONE CYQ I 2 .? 2.8 2.9 3.0 3. I 3.2 MOLECULAR DIAMETER, 8 FIGURE1. Diffusion rates of dissolved gases in polymers. obtained for various gases and vapors in silicone rubber. These data are given in TABLE 3. The diffusion coefficients and gas solubilities are also shown in FIG- URES 1 and 2 along with comparable data for other polymers. It is seen that the solubilities measured are very comparable to those reported for other polymers, and they are also comparable to gas solubilities in many organic liquids. As Hildebrand and Scottg point out, the solubilities increase exponentially with the Lennard-Jones constant for the gases, this constant being closely approximated by the normal boiling point of the gas in degrees Kelvin. On the other hand, diffusion rates in silicone rubber are seen to be almost an order of magnitude higher than diffusion rates for the same gases in the most permeable hydrocarbon polymers. Therefore, the unusually high permeabilities in silicone rubber are mainly due to the high rate of diffusion of the dissolved gases. This property of silicone rubber is a direct result of the greater flexibility or mobility of the Si-0 bond as compared to the C-C or C=C bond characteristic of the polymeric backbone of natural rubber. Robb: Thin Silicone Membranes 123 A DIMETHY L - SI LlCONE 0 8 A 0 0 L.D. POLYETHYLENE (7) 0 POLYCARBONATE (8 1 lop POLYVINYLIDENE FLU ORlDE Ft !% w u t ?? z 0.11: 0: lnW z m3 toA II II I I I I He HP CON, Oe A CH, MI 0 I00 I50 200 LENNARD JONES COEFFICIENT, "K FIGURE2. Gas solubilities in polymers. Direct measurements of gas solubilities in silicone materials with a sorption balance agree reasonably with the solubility values obtained indirectly by the "time-lag" method. McGregorlO has reported solubilities for 0, and N, in dimethyl silicone fluids essentially equal to those reported here, and a value for CO, one-half that reported here. Also, Cannon, St.
Load more

Recommended publications
  • How Chemical Mixtures and Temperature Affect Permeation
    Technical Data Sheet How Chemical Mixtures and Temperature Affect Permeation Selecting appropriate chemical protective clothing and Mixtures ensuring its proper use are important responsibilities of every employer. Standard methods, practices, guidelines, Each combination of barrier and chemical has a characteristic performance criteria and evaluations of hazardous situations in breakthrough time and permeation rate. This unique the workplace can help employers make informed decisions. relationship is due to a combination of physical and chemical However, these decisions can be complicated when mixtures interactions. Mixtures often have chemical and physical are involved or when temperatures vary. That’s because characteristics that are different from those of their additional issues must be considered, including: components. Take the classic mixture known as “aqua regia” (royal water), for example. Aqua regia is a mixture of two • How does permeation change when chemicals are mixed mineral acids. Individually, neither will dissolve gold; but in a together? specific ratio, they will. • On which chemical should permeation be measured? Because mixtures have unique chemical and physical • How does permeation change when the makeup of the characteristics, it is reasonable to expect that the permeation mixture is changed? of the mixtures will be different from the permeation of the components. Some differences can be explained. For example, • How does permeation change when temperature some rubber-like barrier materials swell when exposed to changes? certain solvents. This swelling is a change in the physical structure of the barrier. If there are other chemicals present, Before attempting to address these issues, a review of the permeation might be different because the physical permeation might be useful.
    [Show full text]
  • 30 Years of Membrane Technology for Gas Separation Paola Bernardo, Gabriele Clarizia*
    1999 A publication of CHEMICAL ENGINEERING TRANSACTIONS The Italian Association VOL. 32, 2013 of Chemical Engineering Online at: www.aidic.it/cet Chief Editors: Sauro Pierucci, Jiří J. Klemeš Copyright © 2013, AIDIC Servizi S.r.l., ISBN 978-88-95608-23-5; ISSN 1974-9791 30 Years of Membrane Technology for Gas Separation Paola Bernardo, Gabriele Clarizia* Istituto di Ricerca per la Tecnologia delle Membrane, ITM-CNR, Via P. Bucci, cubo 17/C, 87030 Arcavacata di Rende, CS, Italy [email protected] Membrane technology applied to the separation of gaseous mixtures competes with conventional unit operations (e.g., distillation, absorption, adsorption) on the basis of overall economics, safety, environmental and technical aspects. Since the first industrial installations for hydrogen separation in the early eighties, significant improvements in membrane quality have been achieved in air separation as well as in CO2 separation. However, beside the improvement in the materials as well as in membrane module design, an important point is represented by a correct engineering of these separation processes. The recovery of high value co-products from different industrial streams (e.g. organic vapours from off-gas streams, helium from natural gas) is an interesting application, which created a new market for gas separation membranes, coupling environmental and economic benefits. The opportunity to integrate membrane operations in ongoing production cycles for taking advantage from their peculiar characteristics has been proved as a viable approach. In this ambit, membrane systems in appropriate ranges of operating conditions meet the main requirements such as purity, productivity, energy demand of specific industrial processes.
    [Show full text]
  • Summary of Gas Cylinder and Permeation Tube Standard Reference Materials Issued by the National Bureau of Standards
    A111D3 TTbS?? o z C/J NBS SPECIAL PUBLICATION 260-108 o ^EAU U.S. DEPARTMENT OF COMMERCE/National Bureau of Standards Standard Reference Materials: Summary of Gas Cylinder and Permeation Tube Standard Reference Materials Issued by the National Bureau of Standards QC 100 U57 R. Mavrodineanu and T. E. Gills 260-108 1987 m he National Bureau of Standards' was established by an act of Congress on March 3, 1901. The Bureau's overall goal i s t0 strengthen and advance the nation's science and technology and facilitate their effective application for public benefit. To this end, the Bureau conducts research to assure international competitiveness and leadership of U.S. industry, science arid technology. NBS work involves development and transfer of measurements, standards and related science and technology, in support of continually improving U.S. productivity, product quality and reliability, innovation and underlying science and engineering. The Bureau's technical work is performed by the National Measurement Laboratory, the National Engineering Laboratory, the Institute for Computer Sciences and Technology, and the Institute for Materials Science and Engineering. The National Measurement Laboratory Provides the national system of physical and chemical measurement; • Basic Standards 2 coordinates the system with measurement systems of other nations and • Radiation Research furnishes essential services leading to accurate and uniform physical and • Chemical Physics chemical measurement throughout the Nation's scientific community, • Analytical Chemistry industry, and commerce; provides advisory and research services to other Government agencies; conducts physical and chemical research; develops, produces, and distributes Standard Reference Materials; provides calibration services; and manages the National Standard Reference Data System.
    [Show full text]
  • PREPARATION, CHARACTERIZATION and GAS PERMEATION STUDY of Psf/Mgo NANOCOMPOSITE MEMBRANE
    Brazilian Journal of Chemical ISSN 0104-6632 Printed in Brazil Engineering www.abeq.org.br/bjche Vol. 30, No. 03, pp. 589 - 597, July - September, 2013 PREPARATION, CHARACTERIZATION AND GAS PERMEATION STUDY OF PSf/MgO NANOCOMPOSITE MEMBRANE S. M. Momeni and M. Pakizeh* Chemical Engineering Department, Faculty of Engineering, Ferdowsi University of Mashhad, Mashhad, P.O. Box 91775-1111, Iran. E-mail: [email protected] (Submitted: June 3, 2012 ; Revised: August 13, 2012 ; Accepted: September 22, 2012) Abstract - Nanocomposite membranes composed of polymer and inorganic nanoparticles are a novel method to enhance gas separation performance. In this study, membranes were fabricated from polysulfone (PSf) containing magnesium oxide (MgO) nanoparticles and gas permeation properties of the resulting membranes were investigated. Membranes were prepared by solution blending and phase inversion methods. Morphology of the membranes, void formations, MgO distribution and aggregates were observed by SEM analysis. Furthermore, thermal stability, residual solvent in the membrane film and structural ruination of membranes were analyzed by thermal gravimetric analysis (TGA). The effects of MgO nanoparticles on the glass transition temperature (Tg) of the prepared nanocomposites were studied by differential scanning calorimetry (DSC). The Tg of nanocomposite membranes increased with MgO loading. Fourier transform infrared (FTIR) spectra of nanocomposite membranes were analyzed to identify the variations of the bonds. The results obtained from gas permeation experiments with a constant pressure setup showed that adding MgO nanoparticles to the polymeric membrane structure increased the permeability of the membranes. At 30 wt% -16 -16 2 MgO loading, the CO2 permeability was enhanced from 25.75×10 to 47.12×10 mol.m/(m .s.Pa) and the CO2/CH4 selectivity decreased from 30.84 to 25.65 when compared with pure PSf.
    [Show full text]
  • The Viable Fabrication of Gas Separation Membrane Used by Reclaimed Rubber from Waste Tires
    polymers Article The Viable Fabrication of Gas Separation Membrane Used by Reclaimed Rubber from Waste Tires Yu-Ting Lin 1, Guo-Liang Zhuang 1, Ming-Yen Wey 1,* and Hui-Hsin Tseng 2,3,* 1 Department of Environmental Engineering, National Chung Hsing University, Taichung 402, Taiwan; [email protected] (Y.-T.L.); [email protected] (G.-L.Z.) 2 Department of Occupational Safety and Health, Chung Shan Medical University, Taichung 402, Taiwan 3 Department of Occupational Medicine, Chung Shan Medical University Hospital, Taichung 402, Taiwan * Correspondence: [email protected] (M.-Y.W.); [email protected] (H.-H.T.); Tel.: +886-4-22840441 (ext. 533) (M.-Y.W.); +886-4-24730022 (ext. 12115) (H.-H.T.) Received: 14 September 2020; Accepted: 28 October 2020; Published: 30 October 2020 Abstract: Improper disposal and storage of waste tires poses a serious threat to the environment and human health. In light of the drawbacks of the current disposal methods for waste tires, the transformation of waste material into valuable membranes has received significant attention from industries and the academic field. This study proposes an efficient and sustainable method to utilize reclaimed rubber from waste tires after devulcanization, as a precursor for thermally rearranged (TR) membranes. The reclaimed rubber collected from local markets was characterized by thermogravimetric analyzer (TGA) and Fourier transfer infrared spectroscopy (FT-IR) analysis. The results revealed that the useable rubber in the as-received sample amounted to 57% and was classified as styrene–butadiene rubber, a type of synthetic rubber. Moreover, the gas separation measurements showed that the C7-P2.8-T250 membrane with the highest H2/CO2 selectivity of 4.0 and sufficient hydrogen permeance of 1124.61 GPU exhibited the Knudsen diffusion mechanism and crossed the Robeson trade-off limit.
    [Show full text]
  • Permeation and Its Impact on Packaging
    Room Environment Barrier or Package Product Wall FIGURE 1. Permeation diagram. Permeation and its impact on Packaging Permeation: The migration of a gas or vapor through a packaging material (FIGURE 1.) Michelle Stevens MOCON, Inc. Minneapolis, MN USA IMPACT OF PERMEATION: Shelf life is the length of time that foods, beverages, cases can be avoided with a proper testing protocol. pharmaceutical drugs, chemicals, and many other Under-packaging (inadequate barriers, improper gauges, perishable items are given before they are considered wrong material choices, etc.) allows the transmission unsuitable for sale, use, or consumption. Permeation of some compound(s) at a rate that causes product greatly influences the shelf life of these products as the degradation faster than the desired shelf-life. Repercussions loss or gain of oxygen, water vapor, carbon dioxide and from under-packaging can range from product complaints odors and aromas can rob the product of flavor, color, and returns all the way potentially to voided warranties, law texture, taste, and nutrition. Oxygen, for example, causes suits and legal action. adverse reactions in many foods such as potato chips. By measuring the rate at which O2 permeates through the Over-packaging probably will not result in legal action but package material, one can begin to determine the shelf-life can be a significant waste of money and material resources. or amount of time the unopened package will still provide Often times, a lack of product knowledge will lead a ‘good’ chips. manufacturer to use the best package available within a given budget in order to prevent under-packaging.
    [Show full text]
  • Diffusion in Polar Ice: Observations from Naturally Formed CO(2) Spikes in the Siple Dome (Antarctica) Ice Core Jinho Ahn
    The University of Maine DigitalCommons@UMaine Earth Science Faculty Scholarship Earth Sciences 2008 CO(2) Diffusion in Polar Ice: Observations from Naturally Formed CO(2) Spikes in the Siple Dome (Antarctica) Ice Core Jinho Ahn Melissa Headly Martin Wahlen Edward J. Brook Paul Andrew Mayewski University of Maine - Main, [email protected] See next page for additional authors Follow this and additional works at: https://digitalcommons.library.umaine.edu/ers_facpub Part of the Earth Sciences Commons Repository Citation Ahn, Jinho; Headly, Melissa; Wahlen, Martin; Brook, Edward J.; Mayewski, Paul Andrew; and Taylor, Kendrick C., "CO(2) Diffusion in Polar Ice: Observations from Naturally Formed CO(2) Spikes in the Siple Dome (Antarctica) Ice Core" (2008). Earth Science Faculty Scholarship. 24. https://digitalcommons.library.umaine.edu/ers_facpub/24 This Article is brought to you for free and open access by DigitalCommons@UMaine. It has been accepted for inclusion in Earth Science Faculty Scholarship by an authorized administrator of DigitalCommons@UMaine. For more information, please contact [email protected]. Authors Jinho Ahn, Melissa Headly, Martin Wahlen, Edward J. Brook, Paul Andrew Mayewski, and Kendrick C. Taylor This article is available at DigitalCommons@UMaine: https://digitalcommons.library.umaine.edu/ers_facpub/24 Journal of Glaciology, Vol. 54, No. 187, 2008 685 CO2 diffusion in polar ice: observations from naturally formed CO2 spikes in the Siple Dome (Antarctica) ice core Jinho AHN,1,2 Melissa HEADLY,1 Martin WAHLEN,1 Edward J. BROOK,2 Paul A. MAYEWSKI,3 Kendrick C. TAYLOR4 1Scripps Institution of Oceanography, University of California–San Diego, La Jolla, California 92093-0225, USA E-mail: [email protected] 2Department of Geosciences, Oregon State University, Corvallis, Oregon 97331-5506, USA 3Climate Change Institute, University of Maine, 303 Bryand Global Sciences Center, Orono, Maine 04469-5790, USA 4Desert Research Institute, University of Nevada, 2215 Raggio Parkway, Reno, Nevada 89512-1095, USA ABSTRACT.
    [Show full text]
  • VIKING™ OWNER's MANUAL Vulcanised Rubber & PU Dry Suits for CWD PRO, PROTECH II, HD, HDS, DD & HAZTECH
    Vulcanised Rubber & PU VIKING™ OWNER'S MANUAL Vulcanised Rubber & PU Dry Suits for CWD PRO, PROTECH II, HD, HDS, DD & HAZTECH 1. Safety considerations.............................................................................. 4 1.1 Definitions of important signal words used in this manual ........ 4 1.2 Description of marking in the suit ............................................................... 5 1.3 Pre-dive check list ................................................................................................. 6 1.4 Important safety information ........................................................................ 7 2. Description of suit ..................................................................................... 8 3. Approvals .....................................................................................................11 3.1 EU type approval .................................................................................................11 4. Intended use ...............................................................................................12 5. Selecting and fitting dry suit and underwear.........................13 5.1 Selecting and fitting a dry suit .....................................................................13 5.2 Selecting and fitting dry suit underwear ...............................................13 6. Preparing for the dry suit dive .........................................................15 6.1 Adjusting latex neck seals ..............................................................................15
    [Show full text]
  • DUI PS Cover 4.10
    Introduction.................... RISK MANAGEMENT FOR PUBLIC SAFETY DIVERS PUBLICATION OVERVIEW The goal of this publication is to provide public safety team dive team members with information regarding reducing risk to exposure hazards, decontamination, alternative search tools, training, and personal health/fitness. This publication is geared towards risks posed during search and rescue or recovery operations above and below the surface of the water. DUI has a variety of products to address the exposure and thermal protection needs of the public safety diver and water rescue personnel.This publication is not a public safety “how to” manual. DUI recommends that all team members receive appropriate training for all anticipated team operations from a recognized training agency for public safety diving. If these operations involve activities in a contaminated environment (surface or underwater), dive team members must receive OSHA HAZWOPER training as well.This 40-hour course is available through many sources including local junior colleges and online programs.An 8-hour recertification course is required each year.All team operations should be done in compliance with all federal, state and local regulations. If this guide is unavailable or lost, a copy may be obtained by contacting DUI as follows: Diving Unlimited International, Inc. 1148 Delevan Drive San Diego, CA 92102-2499 USA 800.325.8439 or 619.236.1203 619.237.0378 Fax [email protected] www.DUI-Online.com 1 Table of Contents............................... Publication Overview . 1 Introduction . 3 Team Needs Assessment . 4 Risk Evaluation . 5 a) Contaminants and Effects . 6 b) Hazards . 6 Risk Assessment . 11 Minimizing Risk . 13 a) Exposure Protection .
    [Show full text]
  • Chemical Phenomena
    CHEMICAL 5PHENOMENA Written by Samantha Tjen Designed and edit by Rebecca Sopacua HENRY’S LAW (SOLUBILITY) Explanation: Henry’s Law states that the concentration of a gas dissolved in a liquid is proportional to its partial pressure above the liquid - P is the partial pressure (mole P ∝ C P = k ×C fraction of that gas multiplied by the H total pressure above liquid), determining the amount of gas that goes into liquid William Henry (1774-1836) - C is the concentration of the gas molecules on the surface of liquid - kH is a constant determining the amount of gas that goes out of liquid William Henry was an English chemist, born on December 12, 1775, who proposed the solubility law known as Henry’s Law in 1803. He grew up in Manchester during the Chemical Revolution, when it was found out that air and water are not elements. Henry’s Law can be simply called as Coke’s Law as it explains what happens when you open the seal of a soda can. Pressure drops when the soda can is open and gas bubbles (CO2) will move in and out of the liquid. He was then awarded with the Copley Medal and continued to work on the findings of inflammable mixture of gases for a couple decades long. Through his lifetime, he started to experience neurological pains, which affected his nervous system significantly, making him sleep deprived. Eventually, he died on September 2, 1836. Written by Samantha Tjen Designed and edit by Rebecca Sopacua CHARLES LAW Charles Law states that at constant pressure, the volume of gas will be proportional to the temperature of gas.
    [Show full text]
  • NPL REPORT Review of Measurement and Modelling Of
    RESTRICTED NPL Report <Divisionacronym><Team acronym><RES><serial number> NPL REPORT DEPC MPR 012 Review of Measurement and Modelling of Permeation and Diffusion in Polymers Bruce Duncan, Jeannie Urquhart And Simon Roberts NOT RESTRICTED January 2005 1 of 3 NPL Report DEPC MPR 012 Review of Measurement and Modelling of Permeation and Diffusion in Polymers Bruce Duncan, Jeannie Urquhart and Simon Roberts Division of Engineering and Process Control ABSTRACT Diffusion and permeation in polymeric materials is of fundamental importance in many applications and is the subject of considerable scientific interest. Measurement methods for determining permeation through polymer sheets and within polymeric materials have been reviewed. An overview of the generic mechanisms involved reveals dependence of these properties on a wide range of factors, some relating to the materials others to the exposure environments. There can often be an interrelationship between factors, for example the combination of stress and chemical exposure is often a critical degradation mechanism in the service performance of polymeric structures. Dispersed phases and interfaces play important roles in the mass transport process but the mechanisms are not well understood, limiting predictive capabilities. Modelling is used to supplement experimental measurements, improving understanding and enabling extrapolation of behaviour over timescales and in large components that are not experimentally convenient. Performance 2004-2007 Project deliverable F07/d1 NPL Report DEPC MPR 012 Ó Crown copyright 2005 Reproduced with the permission of the Controller of HMSO and Queen’s Printer for Scotland ISSN 1744-0270 National Physical Laboratory Hampton Road, Teddington, Middlesex, TW11 0LW Extracts from this report may be reproduced provided the source is acknowledged and the extract is not taken out of context.
    [Show full text]
  • Chemical and Biological Tests of Viking Dry Suits and Accessories
    Diving in Contaminated Water, 3rd Edition: Chemical and Biological Tests of Viking Dry Suits and Accessories Trelleborg Viking , Inc. 170 West Rd., Suite 1 Portsmoutth, NH 03801 Toll Free: 800-344-4458 Tel. 603-436-1236 FAX 603-436-1392 email: [email protected] http://www.trelleborg.com/protective/ © 2001 Trelleborg-Viking, Inc. All rights reserved, Boston Fire Department: Fighting a nine-alarm pier fire from below. Rescue diver exiting the water in a PRO 1000 Turbo Dry Suit wearing a Divator Mask equipped with the Gill™ surface breathing valve. New York Police Department dive team during the recovery of evi- dene from TWA Flight 800 Diving in Contaminated Water Table of Contents Glossary of Terms 2 Foreword 3 Test Philosophy 4 Table #1: Chemical Guide 6 Description of Permeation Test Methods 7 Notes on Table #2, page 8: 7 Table#2: Chemical Permeation Test Results on Suit Material and Latex 8 Test Method and Results for Diffusion on Seams 9 Notes on Table #3: Seam Diffusion Table, page 10 9 Table #3: Diffusion through Seams for Viking Suits 10 Notes on Table #4: Risk Levels for Seams and Materials 11 Table #4: Risk Levels for Seams and Suit Materials 12 Test Method and Results for Zippers 13 Table #5: Chemical Penetration Resistance for Zippers 14 Test Method and Results of Viral Penetration 15 Table #6: Biological Penetration Test Results 15 Cuff Ring System and Dry Gloves 16 Permeation Test Results for Gloves 17 Suggested Diving Systems 18 Pro 1000 Dry suit 18 Heavy Duty Suit with attached Helmet Yoke and Valves 18 Heavy Duty Suit with attached Helmet Yoke (no neck seal or valves) 18 Decontamination Recommendations and Considerations 19 Inspection 19 Additional Information 21 The entire contents of this booklet is copyrighted.
    [Show full text]